A collapsible tube is a cylinder of pliable metal which can be sealed in such a manner that its contents although easily discharged in a desired quantity, are protected from contact with air or moisture during the whole of its period of use as a container. Collapsible tubes are widely used as handy flexible packages for pastes and semi-liquids. As the tube is flattened out to expel its contents, the capacity of the tube is proportionately reduced without the introduction of air and the material in the tube does not suffer any deterioration.
Collapsible tubes are made from aluminum, tin coated lead, or lead tin alloy by cold extrusion. They consist of three parts, the main tube, a shoulder to one end of which a screened nozzle with orifice is fitted, and a molded cap to close the orifice, sometimes application of various design are attached to the nozzle with the help of mechanical or hand operated filling machines, the end is sealed by folding and crimping.
Collapsible tube were initially introduced for packing artists oil color. However now its use has spread for packing a wide variety of products. These tubes are used for filling tooth paste, shaving creams, ointment and inks, etc.
Standard and Specification
The Indian Standards Specification IS: 3101-1979, Specification for Aluminum Collapsible Tubes (First Revision) specifies tubes suitable for a wide range of liquids, semi-liquids, pastes and formulations containing soluble constituents. This standard cover only tubes with short screwed nozzles. There are many other types of nozzles and the standardization of some of them, such as eye-ointment tube, has been covered in IS: 7852-1975. IS: 3101-1979 specifies dimensional requirement and tests for aluminum collapsible tubes with short screw nozzle and plastic caps with both buttress and V-threads.
According to this specification the tubes shall be manufactured from aluminum of grade 19500 as per IS: 737-1974 Specification for Wrought aluminum and aluminum alloys, sheet and strip (for general engineering purposes). The cap may be made from molding grade low density or high density polyethylene, polypropylene, polyvinyl chloride, polystyrene or any other thermosetting plastic like phenol formaldehyde. The molding additives or pigment shall not be toxic and shall be compatible with the product packed. The wad may be manufactured from pulp board, faced pulp board, cork, faced cork, rubber, PVC or any other suitable material.